
/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


typedef struct
{
    ngx_uint_t changes;
    ngx_uint_t events;
} ngx_kqueue_conf_t;


static ngx_int_t ngx_kqueue_init(ngx_cycle_t *cycle, ngx_msec_t timer);
#ifdef EVFILT_USER
static ngx_int_t ngx_kqueue_notify_init(ngx_log_t *log);
#endif
static void      ngx_kqueue_done(ngx_cycle_t *cycle);
static ngx_int_t ngx_kqueue_add_event(ngx_event_t *ev, ngx_int_t event,
                                      ngx_uint_t flags);
static ngx_int_t ngx_kqueue_del_event(ngx_event_t *ev, ngx_int_t event,
                                      ngx_uint_t flags);
static ngx_int_t ngx_kqueue_set_event(ngx_event_t *ev, ngx_int_t filter,
                                      ngx_uint_t flags);
#ifdef EVFILT_USER
static ngx_int_t ngx_kqueue_notify(ngx_event_handler_pt handler);
#endif
static ngx_int_t ngx_kqueue_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
                                           ngx_uint_t flags);
static ngx_inline void ngx_kqueue_dump_event(ngx_log_t     *log,
                                             struct kevent *kev);

static void *ngx_kqueue_create_conf(ngx_cycle_t *cycle);
static char *ngx_kqueue_init_conf(ngx_cycle_t *cycle, void *conf);


int ngx_kqueue = -1;

static struct kevent *change_list;
static struct kevent *event_list;
static ngx_uint_t     max_changes, nchanges, nevents;

#ifdef EVFILT_USER
static ngx_event_t   notify_event;
static struct kevent notify_kev;
#endif


static ngx_str_t kqueue_name = ngx_string("kqueue");

static ngx_command_t ngx_kqueue_commands[] = {

    {ngx_string("kqueue_changes"), NGX_EVENT_CONF | NGX_CONF_TAKE1,
     ngx_conf_set_num_slot, 0, offsetof(ngx_kqueue_conf_t, changes), NULL},

    {ngx_string("kqueue_events"), NGX_EVENT_CONF | NGX_CONF_TAKE1,
     ngx_conf_set_num_slot, 0, offsetof(ngx_kqueue_conf_t, events), NULL},

    ngx_null_command};


static ngx_event_module_t ngx_kqueue_module_ctx = {
    &kqueue_name,
    ngx_kqueue_create_conf, /* create configuration */
    ngx_kqueue_init_conf,   /* init configuration */

    {
        ngx_kqueue_add_event, /* add an event */
        ngx_kqueue_del_event, /* delete an event */
        ngx_kqueue_add_event, /* enable an event */
        ngx_kqueue_del_event, /* disable an event */
        NULL,                 /* add an connection */
        NULL,                 /* delete an connection */
#ifdef EVFILT_USER
        ngx_kqueue_notify, /* trigger a notify */
#else
        NULL, /* trigger a notify */
#endif
        ngx_kqueue_process_events, /* process the events */
        ngx_kqueue_init,           /* init the events */
        ngx_kqueue_done,           /* done the events */
#if (NGX_SSL && NGX_SSL_ASYNC)
        NULL, /* add an async conn */
        NULL, /* del an async conn */
#endif
    }

};

ngx_module_t ngx_kqueue_module = {NGX_MODULE_V1,
                                  &ngx_kqueue_module_ctx, /* module context */
                                  ngx_kqueue_commands, /* module directives */
                                  NGX_EVENT_MODULE,    /* module type */
                                  NULL,                /* init master */
                                  NULL,                /* init module */
                                  NULL,                /* init process */
                                  NULL,                /* init thread */
                                  NULL,                /* exit thread */
                                  NULL,                /* exit process */
                                  NULL,                /* exit master */
                                  NGX_MODULE_V1_PADDING};


static ngx_int_t
ngx_kqueue_init(ngx_cycle_t *cycle, ngx_msec_t timer)
{
    ngx_kqueue_conf_t *kcf;
    struct timespec    ts;
#if (NGX_HAVE_TIMER_EVENT)
    struct kevent kev;
#endif

    kcf = ngx_event_get_conf(cycle->conf_ctx, ngx_kqueue_module);

    if (ngx_kqueue == -1)
    {
        ngx_kqueue = kqueue();

        if (ngx_kqueue == -1)
        {
            ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_errno,
                          "kqueue() failed");
            return NGX_ERROR;
        }

#ifdef EVFILT_USER
        if (ngx_kqueue_notify_init(cycle->log) != NGX_OK)
        {
            return NGX_ERROR;
        }
#endif
    }

    if (max_changes < kcf->changes)
    {
        if (nchanges)
        {
            ts.tv_sec  = 0;
            ts.tv_nsec = 0;

            if (kevent(ngx_kqueue, change_list, (int)nchanges, NULL, 0, &ts)
                == -1)
            {
                ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                              "kevent() failed");
                return NGX_ERROR;
            }
            nchanges = 0;
        }

        if (change_list)
        {
            ngx_free(change_list);
        }

        change_list =
            ngx_alloc(kcf->changes * sizeof(struct kevent), cycle->log);
        if (change_list == NULL)
        {
            return NGX_ERROR;
        }
    }

    max_changes = kcf->changes;

    if (nevents < kcf->events)
    {
        if (event_list)
        {
            ngx_free(event_list);
        }

        event_list = ngx_alloc(kcf->events * sizeof(struct kevent), cycle->log);
        if (event_list == NULL)
        {
            return NGX_ERROR;
        }
    }

    ngx_event_flags =
        NGX_USE_ONESHOT_EVENT | NGX_USE_KQUEUE_EVENT | NGX_USE_VNODE_EVENT;

#if (NGX_HAVE_TIMER_EVENT)

    if (timer)
    {
        kev.ident  = 0;
        kev.filter = EVFILT_TIMER;
        kev.flags  = EV_ADD | EV_ENABLE;
        kev.fflags = 0;
        kev.data   = timer;
        kev.udata  = 0;

        ts.tv_sec  = 0;
        ts.tv_nsec = 0;

        if (kevent(ngx_kqueue, &kev, 1, NULL, 0, &ts) == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                          "kevent(EVFILT_TIMER) failed");
            return NGX_ERROR;
        }

        ngx_event_flags |= NGX_USE_TIMER_EVENT;
    }

#endif

#if (NGX_HAVE_CLEAR_EVENT)
    ngx_event_flags |= NGX_USE_CLEAR_EVENT;
#else
    ngx_event_flags |= NGX_USE_LEVEL_EVENT;
#endif

#if (NGX_HAVE_LOWAT_EVENT)
    ngx_event_flags |= NGX_USE_LOWAT_EVENT;
#endif

    nevents = kcf->events;

    ngx_io = ngx_os_io;

    ngx_event_actions = ngx_kqueue_module_ctx.actions;

    return NGX_OK;
}


#ifdef EVFILT_USER

static ngx_int_t
ngx_kqueue_notify_init(ngx_log_t *log)
{
    notify_kev.ident  = 0;
    notify_kev.filter = EVFILT_USER;
    notify_kev.data   = 0;
    notify_kev.flags  = EV_ADD | EV_CLEAR;
    notify_kev.fflags = 0;
    notify_kev.udata  = 0;

    if (kevent(ngx_kqueue, &notify_kev, 1, NULL, 0, NULL) == -1)
    {
        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
                      "kevent(EVFILT_USER, EV_ADD) failed");
        return NGX_ERROR;
    }

    notify_event.active = 1;
    notify_event.log    = log;

    notify_kev.flags  = 0;
    notify_kev.fflags = NOTE_TRIGGER;
    notify_kev.udata  = NGX_KQUEUE_UDATA_T((uintptr_t)&notify_event);

    return NGX_OK;
}

#endif


static void
ngx_kqueue_done(ngx_cycle_t *cycle)
{
    if (close(ngx_kqueue) == -1)
    {
        ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno,
                      "kqueue close() failed");
    }

    ngx_kqueue = -1;

    ngx_free(change_list);
    ngx_free(event_list);

    change_list = NULL;
    event_list  = NULL;
    max_changes = 0;
    nchanges    = 0;
    nevents     = 0;
}


static ngx_int_t
ngx_kqueue_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
{
    ngx_int_t rc;
#if 0
    ngx_event_t       *e;
    ngx_connection_t  *c;
#endif

    ev->active   = 1;
    ev->disabled = 0;
    ev->oneshot  = (flags & NGX_ONESHOT_EVENT) ? 1 : 0;

#if 0

    if (ev->index < nchanges
        && ((uintptr_t) change_list[ev->index].udata & (uintptr_t) ~1)
            == (uintptr_t) ev)
    {
        if (change_list[ev->index].flags == EV_DISABLE) {

            /*
             * if the EV_DISABLE is still not passed to a kernel
             * we will not pass it
             */

            ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                           "kevent activated: %d: ft:%i",
                           ngx_event_ident(ev->data), event);

            if (ev->index < --nchanges) {
                e = (ngx_event_t *)
                    ((uintptr_t) change_list[nchanges].udata & (uintptr_t) ~1);
                change_list[ev->index] = change_list[nchanges];
                e->index = ev->index;
            }

            return NGX_OK;
        }

        c = ev->data;

        ngx_log_error(NGX_LOG_ALERT, ev->log, 0,
                      "previous event on #%d were not passed in kernel", c->fd);

        return NGX_ERROR;
    }

#endif

    rc = ngx_kqueue_set_event(ev, event, EV_ADD | EV_ENABLE | flags);

    return rc;
}


static ngx_int_t
ngx_kqueue_del_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t flags)
{
    ngx_int_t    rc;
    ngx_event_t *e;

    ev->active   = 0;
    ev->disabled = 0;

    if (ev->index < nchanges
        && ((uintptr_t)change_list[ev->index].udata & (uintptr_t)~1)
               == (uintptr_t)ev)
    {
        ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                       "kevent deleted: %d: ft:%i", ngx_event_ident(ev->data),
                       event);

        /* if the event is still not passed to a kernel we will not pass it */

        nchanges--;

        if (ev->index < nchanges)
        {
            e = (ngx_event_t *)((uintptr_t)change_list[nchanges].udata
                                & (uintptr_t)~1);
            change_list[ev->index] = change_list[nchanges];
            e->index               = ev->index;
        }

        return NGX_OK;
    }

    /*
     * when the file descriptor is closed the kqueue automatically deletes
     * its filters so we do not need to delete explicitly the event
     * before the closing the file descriptor.
     */

    if (flags & NGX_CLOSE_EVENT)
    {
        return NGX_OK;
    }

    if (flags & NGX_DISABLE_EVENT)
    {
        ev->disabled = 1;
    }
    else
    {
        flags |= EV_DELETE;
    }

    rc = ngx_kqueue_set_event(ev, event, flags);

    return rc;
}


static ngx_int_t
ngx_kqueue_set_event(ngx_event_t *ev, ngx_int_t filter, ngx_uint_t flags)
{
    struct kevent    *kev;
    struct timespec   ts;
    ngx_connection_t *c;

    c = ev->data;

    ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                   "kevent set event: %d: ft:%i fl:%04Xi", c->fd, filter,
                   flags);

    if (nchanges >= max_changes)
    {
        ngx_log_error(NGX_LOG_WARN, ev->log, 0,
                      "kqueue change list is filled up");

        ts.tv_sec  = 0;
        ts.tv_nsec = 0;

        if (kevent(ngx_kqueue, change_list, (int)nchanges, NULL, 0, &ts) == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_errno, "kevent() failed");
            return NGX_ERROR;
        }

        nchanges = 0;
    }

    kev = &change_list[nchanges];

    kev->ident  = c->fd;
    kev->filter = (short)filter;
    kev->flags  = (u_short)flags;
    kev->udata  = NGX_KQUEUE_UDATA_T((uintptr_t)ev | ev->instance);

    if (filter == EVFILT_VNODE)
    {
        kev->fflags = NOTE_DELETE | NOTE_WRITE | NOTE_EXTEND | NOTE_ATTRIB
                      | NOTE_RENAME
#if (__FreeBSD__ == 4 && __FreeBSD_version >= 430000) \
    || __FreeBSD_version >= 500018
                      | NOTE_REVOKE
#endif
            ;
        kev->data = 0;
    }
    else
    {
#if (NGX_HAVE_LOWAT_EVENT)
        if (flags & NGX_LOWAT_EVENT)
        {
            kev->fflags = NOTE_LOWAT;
            kev->data   = ev->available;
        }
        else
        {
            kev->fflags = 0;
            kev->data   = 0;
        }
#else
        kev->fflags = 0;
        kev->data   = 0;
#endif
    }

    ev->index = nchanges;
    nchanges++;

    if (flags & NGX_FLUSH_EVENT)
    {
        ts.tv_sec  = 0;
        ts.tv_nsec = 0;

        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ev->log, 0, "kevent flush");

        if (kevent(ngx_kqueue, change_list, (int)nchanges, NULL, 0, &ts) == -1)
        {
            ngx_log_error(NGX_LOG_ALERT, ev->log, ngx_errno, "kevent() failed");
            return NGX_ERROR;
        }

        nchanges = 0;
    }

    return NGX_OK;
}


#ifdef EVFILT_USER

static ngx_int_t
ngx_kqueue_notify(ngx_event_handler_pt handler)
{
    notify_event.handler = handler;

    if (kevent(ngx_kqueue, &notify_kev, 1, NULL, 0, NULL) == -1)
    {
        ngx_log_error(NGX_LOG_ALERT, notify_event.log, ngx_errno,
                      "kevent(EVFILT_USER, NOTE_TRIGGER) failed");
        return NGX_ERROR;
    }

    return NGX_OK;
}

#endif


static ngx_int_t
ngx_kqueue_process_events(ngx_cycle_t *cycle, ngx_msec_t timer,
                          ngx_uint_t flags)
{
    int             events, n;
    ngx_int_t       i, instance;
    ngx_uint_t      level;
    ngx_err_t       err;
    ngx_event_t    *ev;
    ngx_queue_t    *queue;
    struct timespec ts, *tp;

    n        = (int)nchanges;
    nchanges = 0;

    if (timer == NGX_TIMER_INFINITE)
    {
        tp = NULL;
    }
    else
    {
        ts.tv_sec  = timer / 1000;
        ts.tv_nsec = (timer % 1000) * 1000000;

        /*
         * 64-bit Darwin kernel has the bug: kernel level ts.tv_nsec is
         * the int32_t while user level ts.tv_nsec is the long (64-bit),
         * so on the big endian PowerPC all nanoseconds are lost.
         */

#if (NGX_DARWIN_KEVENT_BUG)
        ts.tv_nsec <<= 32;
#endif

        tp = &ts;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                   "kevent timer: %M, changes: %d", timer, n);

    events = kevent(ngx_kqueue, change_list, n, event_list, (int)nevents, tp);

    err = (events == -1) ? ngx_errno : 0;

    if (flags & NGX_UPDATE_TIME || ngx_event_timer_alarm)
    {
        ngx_time_update();
    }

    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "kevent events: %d",
                   events);

    if (err)
    {
        if (err == NGX_EINTR)
        {
            if (ngx_event_timer_alarm)
            {
                ngx_event_timer_alarm = 0;
                return NGX_OK;
            }

            level = NGX_LOG_INFO;
        }
        else
        {
            level = NGX_LOG_ALERT;
        }

        ngx_log_error(level, cycle->log, err, "kevent() failed");
        return NGX_ERROR;
    }

    if (events == 0)
    {
        if (timer != NGX_TIMER_INFINITE)
        {
            return NGX_OK;
        }

        ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
                      "kevent() returned no events without timeout");
        return NGX_ERROR;
    }

    for (i = 0; i < events; i++)
    {
        ngx_kqueue_dump_event(cycle->log, &event_list[i]);

        if (event_list[i].flags & EV_ERROR)
        {
            ngx_log_error(NGX_LOG_ALERT, cycle->log, event_list[i].data,
                          "kevent() error on %d filter:%d flags:%04Xd",
                          (int)event_list[i].ident, event_list[i].filter,
                          event_list[i].flags);
            continue;
        }

#if (NGX_HAVE_TIMER_EVENT)

        if (event_list[i].filter == EVFILT_TIMER)
        {
            ngx_time_update();
            continue;
        }

#endif

        ev = (ngx_event_t *)event_list[i].udata;

        switch (event_list[i].filter)
        {
        case EVFILT_READ:
        case EVFILT_WRITE:

            instance = (uintptr_t)ev & 1;
            ev       = (ngx_event_t *)((uintptr_t)ev & (uintptr_t)~1);

            if (ev->closed || ev->instance != instance)
            {
                /*
                 * the stale event from a file descriptor
                 * that was just closed in this iteration
                 */

                ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0,
                               "kevent: stale event %p", ev);
                continue;
            }

            if (ev->log && (ev->log->log_level & NGX_LOG_DEBUG_CONNECTION))
            {
                ngx_kqueue_dump_event(ev->log, &event_list[i]);
            }

            if (ev->oneshot)
            {
                ev->active = 0;
            }

            ev->available = event_list[i].data;

            if (event_list[i].flags & EV_EOF)
            {
                ev->pending_eof = 1;
                ev->kq_errno    = event_list[i].fflags;
            }

            ev->ready = 1;

            break;

        case EVFILT_VNODE: ev->kq_vnode = 1; break;

        case EVFILT_AIO:
            ev->complete = 1;
            ev->ready    = 1;

            break;

#ifdef EVFILT_USER
        case EVFILT_USER: break;
#endif

        default:
            ngx_log_error(NGX_LOG_ALERT, cycle->log, 0,
                          "unexpected kevent() filter %d",
                          event_list[i].filter);
            continue;
        }

        if (flags & NGX_POST_EVENTS)
        {
            queue = ev->accept ? &ngx_posted_accept_events : &ngx_posted_events;

            ngx_post_event(ev, queue);

            continue;
        }

        ev->handler(ev);
    }

    return NGX_OK;
}


static ngx_inline void
ngx_kqueue_dump_event(ngx_log_t *log, struct kevent *kev)
{
    if (kev->ident > 0x8000000 && kev->ident != (unsigned)-1)
    {
        ngx_log_debug6(NGX_LOG_DEBUG_EVENT, log, 0,
                       "kevent: %p: ft:%d fl:%04Xd ff:%08Xd d:%d ud:%p",
                       (void *)kev->ident, kev->filter, kev->flags, kev->fflags,
                       (int)kev->data, kev->udata);
    }
    else
    {
        ngx_log_debug6(NGX_LOG_DEBUG_EVENT, log, 0,
                       "kevent: %d: ft:%d fl:%04Xd ff:%08Xd d:%d ud:%p",
                       (int)kev->ident, kev->filter, kev->flags, kev->fflags,
                       (int)kev->data, kev->udata);
    }
}


static void *
ngx_kqueue_create_conf(ngx_cycle_t *cycle)
{
    ngx_kqueue_conf_t *kcf;

    kcf = ngx_palloc(cycle->pool, sizeof(ngx_kqueue_conf_t));
    if (kcf == NULL)
    {
        return NULL;
    }

    kcf->changes = NGX_CONF_UNSET;
    kcf->events  = NGX_CONF_UNSET;

    return kcf;
}


static char *
ngx_kqueue_init_conf(ngx_cycle_t *cycle, void *conf)
{
    ngx_kqueue_conf_t *kcf = conf;

    ngx_conf_init_uint_value(kcf->changes, 512);
    ngx_conf_init_uint_value(kcf->events, 512);

    return NGX_CONF_OK;
}
